Excavations on a housing estate in inner London have yielded fascinating evidence showing that the southern part of what is now the United Kingdom basked in a Mediterranean climate a quarter of a million years ago.

The excavations, at Hackney in east London, were by scientists from the Royal Holloway College at the University of London and from English Heritage, which advises the government.

Mediterranean natives

Digging 8.5 metres (25 feet) below an estate due for demolition, they found seeds, leaves, pollen, bits of insects and the bones of small fish and animals which had been washed into the river Thames more than 300,000 years ago.

The archaeologists have already identified wood from alder trees, and the bones of slow worms.

They have also found seeds, the remains of a mollusc, and parts of a dung beetle - all species native to the Mediterranean.

...and the new: The site of the dig today

English Heritage says this provides "incontrovertible evidence that this was a time of exceptionally high temperatures in Britain.

"The dung beetles, whose life cycle is interwoven with that of larger mammals, intriguingly suggest that the insects found at Hackney may have shared the temperate Thames floodplain with straight-tusked elephants and rhinoceros.

"The number and range of finds from this period is unprecedented, and confirms that the Ice Age in Britain consisted of phases when drastic rises in temperature occurred."

Balmy

Early analysis shows that over a quarter of a million years ago and for a period of approximately 20,000 years, far from being an icy inhospitable place, southern Britain was as warm as parts of Spain or Italy.

The closeness of the finds to the surface resulted from successive cold and warm periods of the Ice Age, which caused the thawing and raging river to cut down through its bed, leaving the earlier river bank deposits on the high ground.

A dung beetle fragment from Hackney

Significant Ice Age finds were made in Hackney in the 1880s, when archaeologists found several hundred hand-axes made by proto-Neanderthal people.

The team carrying out the present dig says there has never been so much evidence from this period before.

An English Heritage spokesperson told BBC News Online: "It is a very significant discovery, the largest Ice Age collection so far.

"And analysing the phenomenon of the way the land iced over again, this series of phases of warming and cooling, will help us to learn more about what future climate change may mean."